You can get signatures and file suits for almost anything, that's pretty meaningless. If it wasn't an insignificant percentage, they would've done something about it.
They're really the only entity who knows how widespread this is, and is financially incentivized to address it. Additionally, my employer has probably 30,000 of these keyboards in service and it's not a significant issue.
I don't think Apple is too concerned about class action lawsuits over keyboards... They'll settle and pay a little cash, another entirely insignificant number.
